This invention relates generally to golf practice devices for detecting and automatically indicating the face angle of a golf club head during a practice swing at the time of ball impact.
There are a number of golf swing practice devices which determine the face angle of a golf club head at the time of ball impact, however, they are either too complex in construction and therefore expensive to manufacture or they utilize methods for detecting face angle which are not sufficiently accurate or require the use of a special golf club or a golf club with special attachments, thus preventing the golfer from using his or her own clubs. It is a principal object of the present invention to eliminate these disadvantages.
As examples of the prior art, U.S. Pat. No. 3,601,408 issued to Kenneth K. Wright used photosensors and provides circuitry for computing the direction of swing. However, Wright uses two sensors in combination for developing signals in response to the passage of the club head leading edge in order to sense the angular relation of the club head face or leading edge impact, and as such, his face angle sensing means is inaccurate in the sense that it does not take into consideration varying club head velocities.
Another example of the prior art is illustrated in U.S. Pat. No. 3,194,563 which issued to MacKniesh on July 13, 1965. He utilizes a mirror surface which is secured to the club head for reflecting a beam of light back to a series of light sensors for detecting club face angle. However, such a device requires a special attachment of the mirror to the club head, and in addition, when reflected light is utilized for the purpose of detecting face angle, a light-reflective surface of one type or another must always be positioned on the golf club head. Furthermore, when light is reflected back to one of a series of aligned light sensors to measure club face angle, it is obvious that some amount of accuracy in determining the face angle is lost due to the fact that there is spacing between the array of light sensors.
U.S. Pat. No. 4,146,230 issued to Foster on Mar. 27, 1979 discloses a prior art device for detecting club face angle. However, his device is constructed only to read club face angle with approximation, and his device does not automatically provide for velocity correction in reading the face angle. Likewise, U.S. Pat. No. 4,155,555 issued to Fink on May 22, 1979 does not provide automatic velocity correction in reading face angle. With both of these references, their sensors utilized for detecting face angle must be very accurately physically aligned in the base of the respective structures or apparatus, as any physical misalignment of their sensors will give incorrect face angle reading. In addition, these prior art structures cannot accordingly electronically adjust to correct for physical misalignment of their face angle sensors.
Other references of interest are disclosed in my co-pending application Ser. No. 962,757 filed on Nov. 21, 1978 for Golf Swing Training Apparatus.